I don't think so. I wouldn't try to adapt anythign like that, as it sounds like it would only slow things dwon, as all bottlenecks would still exist. And even for ATA, with non-RAIDed hard diasks and optical drives, the bottleneck is not the cable but the drive itself. The only way to increase transer rate is to make sure the HD and CD are on different channels, and buy a faster CD drive.
AGP won\'t fit in PCI-E... unless you use a really good hammer. ~Trotter